1. Field of the Invention
The invention relates to a suspension of a valve plate on a valve rod using a crossbar extending transverse to the valve rod, wherein the crossbar is connected to the valve plate at lateral valve-plate connection points and the at least one valve rod is connected to the crossbar at a or at each valve-rod connection point of the crossbar lying between the lateral valve-plate connection points, and the crossbar has a spacing from the valve plate in a middle section that encompasses the at least one valve-rod connection point of the crossbar and adjacent sections of the crossbar on both sides of this connection point, and
wherein the valve plate can be pivoted relative to the at least one valve rod by a twisting of the crossbar about a pivot axis extending at a right angle to the valve rod and the crossbar twists when the valve plate pivots relative to the at least one valve rod.
2. Description of Related Prior Art
A suspension of the type noted above follows from the embodiment according to FIGS. 3-5 of U.S. Pat. No. 6,471,181 B2. A crossbar to be connected to the valve rod comprises a first plate that has a conical opening for holding the end of the valve rod that is screwed with the first plate. On both sides of the middle connection point with the valve rod, elastic support blocks are attached to the first plate, wherein second plates that are each screwed to the valve plate are attached on the sides of these blocks opposite the first plate. In the elastic support blocks, for example, cylindrical, force-transmitting elements are embedded. Through the elastic support blocks and the embedded force-transmitting elements, tilting about an axis extending at a right angle to the valve rod is made possible, wherein a more uniform contact pressure of the seal of the valve plate on the valve seat is achieved.
Such an ability of the valve plate to pivot about an axis lying at a right angle to the valve rod is advantageous especially for vacuum valves in which, by means of a freely projecting section of the valve rod, a closing force is exerted on the valve plate with which the valve plate is pressed onto the valve seat. The closing force transmitted by the valve rod results in a certain amount of flexure of the valve rod, wherein through a corresponding pivoting (for example, in the region of 0.5°) of the valve plate relative to the valve rod, the parallel alignment of the valve plate relative to the valve seat is achieved and the seal arranged on the valve plate or also on the valve seat is loaded uniformly.
Such vacuum valves with freely projecting valve rods are known, for example, in different embodiments in the form of L-valves. Such freely projecting valve rods are also present in so-called shuttle valves in which the valve rod is pivoted about an axis standing, e.g., at a right angle to the valve rod for displacing the valve plate from its position freeing the valve opening into its position covering the valve opening but lifted from the valve seat.
L-valves follow, for example, are known from U.S. Pat. Nos. 6,431,518, 6,416,037, 6,966,538, 5,641,149, and the non-published German Patent Application DE 10 2008 049 353.8.
Furthermore, from US 2008/0066811 A1, a vacuum valve is known in which a valve plate is connected to first and second crossbars. First piston-cylinder units are used for shifting the valve plate in its plane, in order to bring it from a position freeing the valve opening into a position covering the valve opening but still lifted from the valve seat. Tappets driven by second piston-cylinder units are used for pressing the valve plate onto the valve seat, with these tappets interacting with side ends of the crossbars. The crossbars are connected to the valve plate by connection elements. These have connection arms extending from a connection point with the crossbars on both sides in the longitudinal direction of the crossbar, with these arms being connected at the ends with a common connection leg extending in the longitudinal direction of the crossbar, with this leg being screwed onto the valve plate at several positions spaced apart in the longitudinal direction of the crossbar. In this way, a more uniform force transmission should be achieved in the longitudinal direction of the crossbars.